Apparatus for converting continuous motion into interrupted motion



Feb. 8,1938. P. G. EDWARDS 2,107,373

APPARATUS'FOR CONVERTING CONTINUOUS MOTION INTO INTERRUPTED MOTION .Filed July 1S, 1955 s sheets-sheet 1 8 7 rwendil wa't/z,

associated clic/7c A). )3mm way Inward INVENTOR f.

' BY M I ATTORNEYl Feb. 8, 1938.` 1 P y(.3, EDWARDS 1 2,107,373

APPARATUS FOR CONVERTING CONTINUOUS MOTION INTO INTERRUPTED MOTON I Filkd July 18, 1935 s sheets-sheet 2 INVENTOR BY W ATTORNEY Feb. 8, 1938. P, EDWARDS 107,373

APPARATUS FOR CONVERTING` CONTINUOUS MOTION INTO INTERRUPTED MOTION Filed July 18, 1935 s sheets-sheet. s

Ziffer/'aprem' BY a 6 TTORNEY Patented Feb. 8, 1938 UNlTED STATES PATENT OFFICE APPARATUS FOR CONVERTING CONTINU- GUS MOTION INTO INTERRUPTED M- TION Application July 18, 1935, Serial No. 32,075

i Claims.

This invention relates to .arrangements for changing continuous motion into interrupted motion, More particularly, this invention relates to arrangements for converting continuous rotary motion into discontinuous rotary motion. Still more particularly, this invention relates to arrangements for the conversion of random rotary or oscillatory motion into motion which varies finite and discrete steps.

When viewed from a diilerent angle, this inveN on relates to arrangements for converting' the motion of a device which continuously varies in accordance with, for example, the temperature of some device or apparatus or the resistance or gain of a circuit, into another motion which corresponds to the variable motion but will vary only in finite and discrete steps.

it is often desirable to take some function such as temperature, pressure, resistance, etc. which may be natural in character and may be of a continuously variable nature and change function into interrupted derivatives, peri .ps for the purpose of controlling some apparatus, circuit or equipment in` accordance with the general characteristic of the function. This may be accomplished with the apparatus of this invention. In certain of the embodiments which will he described hereinafter, no external power me he requ'red if the agency of continuous motion possesses sufhcient driving force to cause the this invention to operate properly. Wmere the continuous motion agency has insuilicient driving force, in such case it may be used only a trigger device for the invention, the driving force being supplied externally.

This invention vill be better understood from the detailed descrip-tion hereinafter following when read in connection with the accompanying drawings in which Figures icand lb represent two views of one form of apparatus for converting continuous motion into a corresponding motion which is discontinuous; Fig. 2 represents a perspective of another arrangement for converting; continuous motion into interrupted motion; Figs. 2c, 2b, 2c, 2d, 2c and 2f represent different views of the arrangement of Fig. 2; Figs. 30, and 3l) represent still another embodiment of this invention Figs. ll and 5 represont still l; her embodiments and applications of this invention. Fig. 4 is shown partly in side vic .nd partly, perspective.

Referring to Figs. lo and lb of the drawings, there are illustrated two views of parts of one arrangement lor changing continuous motion, i. e. motion which may continuously change in direction, into interrupted motion, i. e. motion which corresponds in direction to the continuous motion but which varies in finite and discrete steps. The arrangement consists of a driving shaft l which may be assumed to rotate continuously in either direction according to some predetermined function vvith which it is associated, a function such as temperature change, humidity change, resistance change, etc. The shaft l may rotate in a clockwise direction through one or more revolutions or through part of a revolution as, for example, 150 degrees, or it may rotate in counter-clockwise direction through corresponding revolutions or any part of a revolution. From this agency, it is desired to cause another shaft 2, hereinafter called the driven shaft, to rotate in corresponding directions in discrete steps following generally the motion of the driving shaft I. In Figs. la and 1b, this is accomplished by means of a mechanical linkage between the shafts l and 2, which consists of a sliding finger 3 associated with the shaft l but which at the same time rests in a slot 4 associated with the shaft 2. The finger 3 is held in contact with the inner surface of the slot 4 by means of a spring 5 which continuously applies pressure along the inner surface of slot 4. This applied pressure, when sufciently great may cause the rotation of the shaft 2 in one or more discrete steps, as will be explained more fully t hereinafter.

The shaft 2 may have associated with it a dial the back or left-hand side of which may have a plurality of depressions uniform in depth and positioned circumferentially about the axis of the dial 6, the dial 6 being concentric with the shaft 2. Each of these depressions, shown somew what schematically by dotted lines in the drawings, is deep enough to receive the ball of the click device l of a kind well known in the art. The ball of the click device 'l will generally remain in one of the various depressions for some finite time interval. It will be observed that the ball of the click device is retained in any one of the various depressions of the dial by a spring 8 which continuously applies pressure to the ball. In accordance With this arrangement, the shaft 2 and its associated concentric dial 6 have a tendency to remain in a fixed position until suflicient torque is applied to the shaft v to overcome the resisting effect of the spring 8 of the click device. When sufficient torque is so applied, the dia-l E and its shaft 2 will rotate through one or more steps in a direction correspending to the rotation of the shaft l and the t step or steps of rotation will be determined in general by the torque applied to the shaft 2. The ball ci the click device 'l will come to rest in one of the depressions only when the torque of the shaft 2 is unable to overcome the resisting force of the spring I3.

Assume that the dial 5 is keyed to the shaft 2 and rests in one of its numerous possible positions and that the shaft l then starts to rotate from the position shown in the figure in either direction as, for er; Ae, in a. clockwise direction when looking fro the right hand side of the figure to the left. The finger 3 will also move in a clockwise direction but its left-hand end will ride on the surface oi the slot Il, thereby applying pressure to the spring at the righthand end or" the nger 3. As the spring 5 becomes c i'essed a gradually increasing torque will be ertcd on the shaft .2 in a direction, i. e.

corresponding to the rotation of the The amount oi pressure applied to the spring will be determined, in part, by the shape of the slot i and it will be apparent that the developed torque will bear a predete mined relae tion to the angle oi rotation of the shaft l. A point will be reached where ti is developed torque is sufficient to overcome the resisting or retainm ing action of spring S of the click device i. When this occurs, the dial 5 and the associated shaft 2 will be rotated in a direction corresponding to the rotation of trie shaft I, i. e. clockwise. The ball of the click device i will leave the depression in which it rested and will, in due course, assume a corresponding position in the next dial depression. Thus, the dial S and the shaft 2 will ad Vance one ster.` in the direction of rotation of the shaft I. The finger 3 will be returned substantially to the bottom or the slot l and, moreover, the pressure oi the spring 5 will then again be a minimum.

'if the driving shaft I is further rotated in the same direction, a point may again be reached at which the left-hand end oi the pin E will ride along the inner surface of the slot and thereby apply a clockwise torque to the shaft 2 and dial 6 sufcient to overcome the retaining action of the spring S of the click device. rihen, the ball oi the click device will be allowed to move into another depression, and so on.

It will be also clear that the drivinet shaft may be moved or rotated in the opposite direction, e. counterclockwise, and when this occurs the finger 3 will ride along the opposite internal wall of the slotted device l and apply torque in a counterclockwise direction to the shaft 2 and the dial S. If this counter-clockwise tordue is sufliciently great, the ball of the click device 'i will be moved out of the depression in which it rests and into another dia-l depression.

It will be apparent, therefore, that the driving shaft i may rotate in either direction through part of a revolution or through one or more revolutions and it will produce discontinuous rotation of the shaft 2 and the dial l?, in a corresponding direction, the latter rotation being in iinite steps determined by the spacing of the circumferential depressions at the left-hand side of the dial 6 and by the click device Thus, a continuous torque is converted into a discontinuous torque which may recur through several steps or continuously.

t will be clear that if the slotted member i is incorporated in a device so that the pin 3 is normally spaced at a greater or lesser distance from the driven shaft the number of depressions traversed by the ball 'I of the click device will be changed. This is based on the assumption that the spacing and shape of the depressions iii the dial E and the pressure of the spring 8 remains unchanged. In order that the modified arrangement opera-te properly, the shape of the slot 4, the distance of the pin 3 from the shafts l and 2 and the normal pressure of spring 5 must all be suitably proportioned.

In Figs. 2, 2a, 2b, 2c, 2d, 2e and 2f, a somewhat different arrangement for changing continuous motion into discontinuous motion is shown. The arrangement contemplates two racks II and I2, driving and driven racks, respectively. These may be two discs, driving and driven discs, respectively. In other Words, the reference characters II and l2 may designate the driving and driven racks or the developed edges of these racks or the corresponding developed edges of discs laid out in a straight line. If discs or the like are employed, they may be concentrically arranged and spaced from each other by a small distance.

The rack II may be associated with some continuously changing function, such as temperature, pressure, resistance, gain or the like from which it is desired to impart to the rack i2 corresponding motion but interrupted in nite steps. In order to accomplish this, there are associated with the racks I I and I2 roller devices I3 and I4 which ride along the surfaces or edges oi both driven and driving racks. These roller devices are held in contact with the teeth or edges of the racks by means of compression springs I5 and IS, respectively. One end of each spring is immovable but the other end will, in part, control the pressure applied to one or both of the roller devices.

A slot l? may be associated with one of the racks, for instance, the driven rack, and a pin it may be associated with the other rack, for example, the driving rack. The pin i8 is actually fixed to the driving rack and it extends inte the slot I'I of the driven rack so as always to remain between the two vertical (or radial) sides of the slot I? or at times in Contact with one of these sides. In other words, the pin I8 may move within the limits determined by the sides of the slots Il and never beyond these limits. It will be shown hereinafter that the driven rack which contains the slot Il, will oe moved in one direction or another through one or more finite steps as the pin I3 oi the driving rack repeatedly comes in contact with one of the sides oi the slot Il.

In all of the Figs. 2, 2a, 2b, 2c, 2d, 2e, and 2f, the driving rack II and the pin I8 are shown in dotted lines so as to be readily distinguishable from the driven rack l2 and the slot I'I of the driven rack. In Fig, 2b, for instance, the edges of the two racks are shown in the Same relative positions but these edges are spaced by a small distance in the drawings merely for the purpose of again distinguishing one of these racks from the other,

Each of the rollers I3 and i4 may rest either on the peaks ci teeth of the racks as shown in Fig. for instance, or in valleys between the two adjacent teeth, or one may rest on the peak of a tooth and the other in a valley as shown in 2b. When in any of these positions, the rollers i3 and i4 may be considered in stable equilibrium. When one of the rollers, for example, roller I3, is displaced from the peak of tooth of the driven rack I2, as in Fig. 2c, it will cause this rack, i. e. the driven rack, to move in one direction or the other until this roller eventually reaches a valley between teeth and accordnes to rest in a state of equilibrium in for some finite time interval.

f the pin i3 oi the driving rack has been br ught into contact with the right-hand of slot il oi the driven rack. The driven rack is 'Tore ready to step to the right. Immediately when this contact is established and somewhat earlier, the ifi rests on the peak of a tooth of the driving rack ii while the roller E3 rests on a. peak a tooth of a driven rack I2.

as the driving rack li continues to advanc the ight somewhat after the pin i8 contacts tne right-hai d oi' slot il, the pin It will ce ev the rack iii, which contains the slot, corresponding direction, namely, The roller i3 will then ride down the sine ci the tooth of the driven rack upon which it formerly rested until the roller reaches the valley between that tooth and the next ad-- jacent tooth. This will advance the driven l2 to the right through a distance which correspends to the width ci onedialf of a tooth so that tive positions of the rollers I3 and I4 w'll then be shown in Fig. 2b.

it will be noted that the racks are caused to move in one particular' lateral direction, that is, to the right or to the left, while the rollers I3 iii cove only in perpendicular directions. The ma travel of either roller corresponds to the distance between the peak of a tooth and the valley bctween two teeth.

As the driving rack continues to advance to the rignt roller will remain upon the peak oi' the same tooth oi the driven rack $2, but the roller will be caused to ride up the side of the tooth ci the driving rack il. When the roller I3 is ap Jrcrimately half way up the side of the revt tooth, the relative positions oi the various parts wile as shown in Fig, 2c. It will be noted that the drivinCr rack ll has just left the roller i-l upon a 'tooth upon which it rested in the position shown Fig. 2b and that the roller I3 has left the driven rack li in the valley in which it rested in the position shown in Fig. 2b.

When the driving rack ii has moved to the rig t a distance sufficient to bring the roller i3 to the peak of the tooth with which it was associated in 2c, the roller i4 will then. remain at rest upon the peak oi a tooth of the driven rack. This is shown in Fig. 2d. The pin Iii will then be at or very close to the right side of the slot il of the driven rack I2. The arrangement of the parts as shown in Fig. 2d corresponds very closely to that shown in Fig. 2o: except that the rollers i3 and M rest upon the peaks of teeth of the driving and driven racks, respectively, in 2d but in Fig 2o these rollers rest upon teeth of 'the driven and driving racks, respectively.

the driving rack il continues to move to t right, the driven rack will be moved to the right through a distance which corresponds to the width ci one-half of a tooth. The pin of the driving rack will. :ren assume a position aptely midway between the sides of the i 7en rack. At the same time the down the left side or" the tooth upon which it lcrmerly rested and assume a position in the valley between that tooth and the next adjacent tooth to the left. in this position the roller will in the valley between adjacent teeth of both the driving and driven racks. The roller then assumes a position upon the peaks of corresponding teeth of both the driving and driven racks. This is the arrangement shown in Fig. 2e.

As the driving rack I I continues to move to the right, the roller I4 will ride up the right side of the next adjacent tooth to the left, thereby leaving the driven rack I2. The roller I3 will remain upon the peak of a tooth of the driven rack where it was left by the driving rack II upon which it formerly rested. The relative positions of the pin I8 and the slot I'I as the roller I4 is half way up the side of the tooth upon which it is now riding are shown in Fig. 2f. Thereafter, further movement of the driving rack to the right will cause the rollers I3 and I4 to assume the positions shown in Fig, 2a.

In the foregoing description of Figs. 2a to 2f, inclusive, the driving rack II was described as moving to the right. It will be understood that the driving rack may equally well move to the left and the locations of the various parts will assume corresponding positions which will be apparent from the description already furnished. The driving rack I I may at times remain station ary and during any such intervals the various parts will remain ln their former positions and, ci course, stationary.

The driven rack I2 is expected to move in finite steps in a direction corresponding to the continuous motion of the driving rack II. In order to be sure that the. driving rack will always operate in finite steps, a form of click device may be associated therewith. In Fig. 2a, the click device comprises a rack I9 having twice as many teeth as there are in the driven rack, a roller and a spring 2 I. The rack I9 is directly coupled to the driven rack I2 in any well known manner. As the driven rack is moved in either direction through a distance which corresponds to the width of onehalf of one of its teeth, the auxiliary click device will also be moved through a corresponding distance which in the case of the click device will represent the distance between two of its adjacent teeth. Thus the roller 20 will not be allowed to rest upon the peak of any of its teeth but will readily assume a position within the valley between adjacent teeth. The pressure of the spring 2l behind the roller 20 will assist in maintaining such a condition throughout the operation of the apparatus. This same auxiliary click device is shown in each of the other Figures 2h to 2f, inelusive, and as shown in this arrangement the roller 20 is always in the same position between the valley formed by two teeth.

The driving and driven members need not be racks as suggested by Figs. 2a to 2f, nor need they be laterally moving devices of any type whatever. These members may be rotatable` devices such as gear wheels or notched devices, one form of which is shown, for illustrative purposes, in Fig. 2.

In Fig. 2 the driving and driven rotatable members II and I2, respectively, have toothed projections with which the cylindrical roller devices I3 and I4 are brought into contact in much the same manner as is illustrated in Figs. 2a to 2f. The. cylindrical devices I3 dand I4 are mounted in reciprocating elements or arms 22 and 23, respectively, as shown, these reciprocating elements 22 and 23 being rotatable about the immovable shafts 25 and 26, respectively. The elongated pin I 8 is permanently fixed to the driving member I I at one end, the other end of the pin I8 being freely movable between the sides of slots I'I, formed in the driven member I2. The springs I5 vand I6 maintain the devices I3 and. I4respectivcly, in

contact with the toothed projections of the driving and driven members II and I2.

The toothed member' Ii] is fixedly coupled mechanically to the driven member' I2. The member l5 forms part of the click device, referred to above with respect to Figs. 2o, to 2f, and it has twice as many teeth as there are on members I I and l2. The cylindrical device 35 is mounted in the reciprocating element cr arm 24, which is also rotatable about the immovable shaft 25. The device is maintained continuously in Contact with the periphery of member l by virtue of the tension in the spring 2i.

The. continuous rotation of th e member il will cause the normally LLee end o the pin I8 to contact one side of slot l? intel 'ttently, each such contact `producing thereafter a partial rotation of the member li in a similar direction. lThe rotary motion of member i2 will cause the member i9 to rotate through a similar angie. The operation of the arrangement shown in Fig. 2 will correspond to that of the arrangement of 2a to 2,1', already described hereinabove.

Figs. 3a and 3b show still another arrangement for converting continuous motion into interrupted motion, but in this arrangement power is supplied from an external source to operate the arrangement. The continuous motion of the driving shaft 3l is enabled to control the interrupted motion of the driven shaft The external power is supplied from any available source to the shafts 33 and 3d which cause the wheels 35 and 35 which carry pins 3l' and 38 to rotate in mutually opposite directions, as indicated by the arrows associated with these wheels. The wheel 35 may be considered to rotate in counter-clockwise direction and the wheel 3E in a clockwise direction.

A toothed wheel 39 is mounted on the shaft 43 which may be considered to couple the driving shaft BI to the driven shaf 32. The shaft 4E! has a narrow slot il within which a pin l2 mounted on the driven shaft 32 may slide. Thus the wheel 39, by virtue of its mounting upon shaft 49 and by virtue of the relationship of pin l2 and slot will be enabled to slide along the driven shaft 32 but will have no free rotary motion with respect to the driven shaft In other words, the wheel 39 will rotate the shaft 3i' whenever the wheel rotates and the shaft 32 will remain Stationary whenever the wheel 39 is stationary. t is possible, however, for the wheel 39 to slide. along the shaft within the limits defined by the slot 4I as will be pointed out hereinafter.

The driving shai't is threaded at 43 as shown and for the of convenience of description, it may be assumed that this threading is that of a normal right-hand thread. The threaded shaft 3l engages the corresponding female threading i4 of the shaft d. As the shaft 3 rotates, let us assumo, in a clockwise direction, the engagement of its threads i3- with the corresponding threads dfi of the shaft fifi will cause the shaft '55 and the wheel 39 mounted thereon to move toward the driving shaft 3l. As the shaft 3l is rotated in a counter clockwise direction, wheel 3S will be moved away from the driving shaft 3l. It may be assumed that the threading of the members d3 and 54 is of course of steep pitch in order that only small angular rotation of the shaft 3I will provide a large lateral movement of the wheel 39.

When the shaft 3l is moved, for example, a clockwise direction, through an appreciable angular distance, the teeth of the. wheel 39 will be brought into engagement with the pin 31 of the Wheel 35. As the pin 3l continuously rotates in a. counter-clockwise direction, it will strike one of the teeth of the wheel S9 and advance the wheel 39 in a clockwise direction through one step, that is a distance corresponding to the spacing between two of the teeth of wheel 39. As the wheel is directly coupled to the driven shaft 32, ne shaft 32 will also be driven in a clockwise direction through an angle corresponding to the rotation of the wheel 39.

After the wheel 39 has been rotated as already described, it will at the same time produce a relative motion of the shaft 40 with respect to the driving shaft 4I sufiicient to cause the wheel 33 to clear the pin 3'! of the wheel 35. However, if the driving shaft SI continues to rotate in the same direction, that is, clock' ise, the wheel S9 will soon again be rotated in a clockwise direction after it again strikes the pin 3l and this will again rotate the driven shaft 32 through a corresponding angle.

If the driving shaft 3| then rotates in the opposite or counter-clockwise direction, the wheel 39 will be moved away from the shaft 3l and it may later strike the pin 38 of the wheel 3E which is rotating in a clockwise direction. When this happens, the wheel 39 will be rotated in a counter-clockwise direction for an angular distance corresponding to the spacing between two of its teeth and it will carry the driven shaft 32 through a corresponding angle of rotation.

As shown in Fig. 3b, as long as the wheel 39 remains spaced from the contacts 3l, 38, it will not be rotated in either direction and therefore the shaft 32 shown in Fig. 3a will remain stational-y. The wheel 39 will be rotated only when it is moved laterally through a distance which will cause it to engage either of the pins 3l or 38,

The relation of the number of teeth included on wheel 39 to the pitch of the thread 3 may such as to return wheel 39 midway between pins 3T and 38 or to any other desired position. In fact the steps ma;1 be sufficiently large as to return wheel 3S more than the distance between pins 31, 38, thus establishing a hunting condition of the device. In the latter if shaft 3l remained stationary the wheel 39 would move back and forth successively so that t the end of each movement it would engage pins 3l and 38.

Fig. 4 illustrates a modification of the arrangement shown in Figs. 3a and 3b. In this arrangement, it is proposed to change the resistances 50 step by step as the resistance of the pilot wire 5I of a toll cable changes in appreciable amounts.

The resistances 50 are connected as one arm of a Wheatstone bridge, this arm also including a rotatable arm 52 which is mounted on and elcctrically connected to the sha-ft The other variable arm of the Wheatstone b idge includes the pilot wire 5l. The battery or other source of direct current 53 is connected as one diagonal of the Wheatstone bridge. The other diagonal of the Wheatstone bridge includes the winding of a voltmeter relay 54 which may be oi any well known type.

The toothed wheel 39 is mounted on the shaft el) and, as in Figs. 3a and 3b, the shaft 3 is ccnpled to the shaft 32 by means of the slot @I and the pin $2. The shafts 4i) and 32, are, however, electrically insulated from each other at 55. Two solenoids 56 and 51 are mounted on opposite sides of the toothed wheel 39 and current may flow from a source or battery 58 through the lay windings of either of these solenoids. Upon the energization of either of these solenoids, the iron shaft 4B will be moved in the direction of the solenoid energized. Thus, when the solenoid 55 is energized, the toothed wheel 39 will engage the pin 31 oi the continuously rotating wheel 35, or if the solenoid l' is energized, the wheel 35 will engage the pin 3S of the wheel 36 which continuously rotates in the opposite direction.

When the Wheatstone bridge is substantially in balance, little or no current will flow through the winding of the voltmeter` relay 5d and its armature will be spaced from the associated contacts. Under such conditions, the resistance oi the pilot wire 5| may be equal to or bear a fixed relationship to the resistances Si! at the left of the movable arm 52.

When the pilot wire resistance chances as, ior example, when it increases appreciably, the bridge will become unbalanced and the armature will be attracted to one of its contacts, for example, the lower contact. Current will then how from the battery 58 through the windings of the solenoid 5S and over the armature and lower contact of the voltmeter relay Upon the energization of the solenoid 56, the wheel 39 will be moved toward this solenoid and promptly one of the teeth of the Wheel 39 will engage the pin 31, thereby rotating the Wheel 39 in a clockwise direction when viewed from the right-hand side of the gure. The shaft 32 and the arm 52 will also be rotated through a corresponding angular distance in a clockwise direction and therefore, the resistances 5t* will be increased by one step.

If the Wheatstone bridge then becomes balanced by the additional resistance at 5U, the voltmeter relay lill will become deenergized and its armature will then become spaced from its con-- tacts. No current will then flow from the source 58 through the solenoid 5@ and the wheel 39 will remain spaced from the pins 3'.' and 38.

Upon `further unbalance oi the Wheatstone bridge because of further increase of the resistance in the pilot wire 5i, the bridge will then become unbalanced and current will again flow from the source 55 through the solenoid The wheel 39 will again engage the pin 37 and thereby become rotated in a clockwise direction so to further increase the resistance at 50. Thus, the resistance at 5i! Will be increased step by step until a balance is produced in the Wheatstone bridge.

When the unbalance of the Wheatstone bridge due to an appreciable reduction in the resistance in the pilot Wire 5i, the armature of voltmeter relay 5i! will close its upper contact and current will then flow from the source 5S through the windings of the solenoid` 5l' and over the armature and upper Contact of the re- This will attract the wheel 39 and cause it to engage the pin 38 which will in turn rotate the wheel 39 in a counter-clockwise direction. Consequently, the arm 52 will be rotated so to reduce the resistance at 5G. Thus, as the pilot wire resistance becomes reduced. the apparatus will reduce the resistance at 5?! step by step until the bridge becomes eventually balanced.

Obviously if the steps of resistance 50 are sufciently large, voltmeter relay 54 will never remain in an uncontacted position and a hunting condition of the device will also obtain as described in connection with Figs. 3a and 3b.

Fig. 5 shows another arrangement to which this invention may be applied. The pilot wire 5i and the right-hand portion of the resistance 6D together form one arm of the Wheatstone bridge. The left-hand` portion of the resistance 50 and an additional resistance 6| together form another arm of the bridge.

As the bridge becomes unbalanced, the relay 54 will cause its armature to close either of its associated contacts. Thus, as the resistance of the pilot wire increases, the upper contact of the relay 5a may be closed and as the pilot Wire resistance decreases, the lower contact oi that relay may be closed. The upper contact is in series with the field winding 62 of a reversible motor as well as with its armature winding 63. The lower contact of the relay 5 is in series with the field winding 64 as well as with the armature winding 63 oi the motor. Thus the direction of rotation of the motor is controlled by the voltmeter relay 5ft Current for energizing these windings is supplied by battery or other source 65,

fis the motor is rotated continuously in one direction. or the other, it will rotate the shaft il which is coupled to another shaft 32 through a device S5 which may include any of the mechanical coupling devices shown in Figs. la and lb or 2a to inclusive, or 3c and 3b. Thus, the apparatus St may include any device for convertim7 continuous rotary motion into discontinuous rotary motionv rotated or operated step by The driven shaft 32 is coupled to but insulated from an arm 61 which may control the connection of any one of a plurality of impedances E58, 69, l0, 1|, 72 or 'i3 across the input of amplifier la for controlling the gain, phase or frequency characteristic separately and collectively of the cable circuit to which this amplier is connected. Thus, it will be seen that the step-by-step rotation of the shaft 32 Will quickly connect across the input of the amplier "iii any one of the equalizing pads ES to 13, inclusive.

While this invention has been shown and decribed in certain particular arrangements merely for the purpose of illustration, it will be understood that the general principles of this invention may be applied to other and widely varied` organizations Without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. The combination of a first toothed movable element, a second toothed movable element arranged so as to move in the same direction as said first element, means including a member movable substantially transversely with respect to the direction of motion of said movable elements for producing a lost motion coupling between said elements, means for moving the rst element continuously, and means including said rst named means and responsive to the motion of the first element for moving the second element in nite steps in the direction or" motion of the first element.

2. The combination of two concentric rotatable eiements, a normally untensioned pin movable in a direction concentric with respect to the direction of rotation of said rotatable elements, one end oi said pin being supported by one of said elements, a slot in the other rotatable element, the other end of said pin being normally free from pressure and being normally positioned in spaced relation to both sides of said slot, means responsive to the rotation of the element supporting the pin for bringing the pin into contact with one of the sides of the slot, a click device for controlling the rotation of the rotatable element carrying the slot, and means responsive to the further rotation of the rotatable element supporting the pin for rotating the other rotatable element in nite steps determined by the click device.

3. The combination of a toothed rotatable element, grooved means rotatable step by step in response to the rotation of said element, and coupling means including a member periodically contacting the periphery of said element and movable in a direction Which is substantially transverse with respect to the axis of rotation cf said element and including means for periodically contacting said grooved means.

4. The combination of two movable elements, a normally untensioned pin mounted on one of said elements, the other of Said elements having slot Within which the pin may move Within predetermined limits, the pin being normally free from pressure and being normally spaced from both sides of the slot, means responsive to the motion of the element upon which the pin is mounted to move the pin periodically into contact with one of the sides of the slot, and means for moving the slotted element through steps of predetermined size as the pin periodically contacts one of the sides of the slot.

5. The combination of two mechanically coupled rotors having teeth along their periphery, a pair of rollers resiliently mounted about both of said rotors and movable only in directions substantially perpendicular to the axis of said rotors, and means responsive to the continuous rotation of one of said rotors to drive the other rotor step by step.

6. The combination of two toothed members mounted so as to be movable with respect to each other, two rollers movable under pressure over the teeth of both members in directions substantially perpendicular to the movements of said members, a pin xedly mounted on one of said members and movable within a slot in the other member, and means controlled by said rollers for driving one of said members by nite steps as the other member moves its pin intc Contact with one side of the slot.

7. The combination of tivo coaxial toothed Wheels, means including two rollers mounted diierent points along the teeth ci said toothed Wheels so as to apply pressure to said toothed Wheels substantially transversely with respect to the axis of said toothed Wheels, means for continuously driving one of said toothed Wheels, and means including a click device coupled mechanically to the other toothed wheel to rotate the latter toothed wheel through finite angular steps determined by the spacing oi thc teeth oi said toothed wheels.

PAUL GRIFFITH EDWARDS.

Cil 

